The present invention relates to installing in-ground support footings around upstanding elongate objects such as structural poles, post, pilings and the like, to enhance structural integrity thereof, and more particularly to a novel method, apparatus and assembly for installing a cylindrical casing around subterranean and above-ground portions of an elongate object without the necessity for cutting, moving or otherwise disturbing the elongate object.
The present invention is directed to providing support footings for any type of existing ground-supported elongate object, however, the present invention is particularly suited for reestablishing adequate structural support to deteriorated or damaged utility poles and power transmission line towers. Utility poles are usually wooden, and may become structurally-weakened and inadequate to support utility lines, such as electrical power lines and telephone lines as well as transformers, etc.,--an obviously unsafe condition. Deterioration often occurs in utility poles after they have been disposed in the ground for several years, and "groundline rot" caused by moisture, insects and fungi, may extend in poles from just above the ground and thereinto up to two feet or thereabouts. The pole is essentially rotting around its ground-supported base and becomes structurally very weak, not only from a column standpoint but also in bending or shear strength.
Utility poles may also become split or fractured and structurally weakened after being struck by livestock (in rural areas) and/or vehicular traffic. Moreover, utility poles located along streets, highways, alleys or other thoroughfares are close to traffic and subject to being hit by automobiles and trucks, and thereby damaged.
Obviously, utility poles weakened by groundline rot or fracture present a dangerous situation which is to be avoided--and various techniques have been proposed and practiced to prevent weakened or damaged utility poles from becoming toppled.
The most basic technique involves replacement of a deteriorated or damaged utility pole with a new pole. This technique requires that the utility lines be disconnected from the top of the pole--resulting in discontinuance of service. The pole is then held by some type of grapple or other device, and is cut at its base. The pole is then removed, the underlying stump dug up, and a new pole is repositioned in the same hole from which the stump was removed, because the lines must be supported at the same general location, when reinstalled on the new pole. It can be appreciated that removal of the old pole and transport of the new pole for replacement are time-consuming and expensive steps in and of themselves. Furthermore, because of the nation's dwindling timber resources and environmental pressures, replacement poles are difficult to procure and expensive.
In an atttempt to answer the basic problems attendant with the replacement pole technique, it has been proposed to strengthen an existing, structurally-weakened pole by "stubbing" the pole and providing an in-ground support footing defined by a grout-filled casing. The "stubbing" technique requires that the weakened pole be held firmly adjacent its top by means of some type of boom assembly. The pole is then "stubbed" by cutting the pole off at its base or butt by means of a chain saw or other cutting device. The boom is then operated to hold and shift the pole to the side of the stump or "stub," and this may be difficult to do without disturbing the line connections. Next, an anchoring system is employed requiring a specialized apparatus including a rotatable driver mounted for rotating a casing over the stub. The casing is secured at its top edge to a rotatable driver, and the casing may be thought of as a large helical thread. The casing has a diameter greater than that of the pole and it is rotated and driven down around the stub for a predetermined distance, so that the casing surrounds the damaged area of the "stub," i.e., until the top of the casing is positioned one foot or thereabouts above the ground.
Next, the rotation device is uncoupled from the top of the casing and an upwardly extending sleeve is attached thereto. The remainder portion of the pole, which has been held continuously by a crane or boom, is then inserted into the sleeve until its bottom engages the top of the "stub." Thereafter, grout and sand is dispensed into the annulus between the interior walls of the casing and the "stub" and upwardly into the annulus defined between the interior walls of the sleeve and the pole. It should be appreciated that the stubbing technique suffers from several significant drawbacks, namely, the pole must be cut and supported by a boom and shifted to one side, possibly requiring disconnecting of lines, with the consequent discontinuance of service. In addition, the lines must be reconnected and the entire process requiring pole-holding, "stubbing," line disconnect-connect, etc. is time-consuming and expensive.
Another prior-art repair method, also requiring pole cutting or "stubbing," is that known as the "mod pole" technique which proceeds along the following steps. First, a utility pole in need of repair is supported by a stabilizing device, and the pole is then cut off above the ground line. The pole is moved to the side of the "stub" by the stabilizing device and the utility lines are temporarily disconnected from service. Next, the "stub" is removed and a prestressed concrete pole base is implanted in the cleaned-out void left by the original pole. Alternatively, if it is desired to move the pole to a new position, a new hole must be dug. A prestressed, concrete pole replacement base is implanted in the cleaned-out void or new hole, as the case may be, and the supported pole is then moved for attachment to the replacement base. Afer this procedure has been completed, service is reconnected.
All of the above-described repair techniques contemplate that utility poles must be modified in some manner, i.e., by complete replacement or "stubbing," and it is apparent that a technique for establishing an in-ground footing around a utility pole, without replacing, cutting or otherwise modifying that pole would provide significant advantages.
Accordingly, it is a general object of the present invention to provide a novel casing means for installation as an in-ground support footing around a pole by using a method and apparatus which does not require removal or "stubbing" of the pole. More specifically, the present invention is directed to a method and apparatus for installing the casing means which contemplates positioning the casing means, which includes helical thread means at a lower end thereof, for assembly as a hollow, cylindrical casing around the pole. The casing means includes separate components, such as partial or half-cylinders complementary for being moved toward one another laterally inwardly toward the pole and assembled in a cylindrical and unitary final configuration surrounding the above-ground lower region of the pole. The casing means is then gripped by an assembly or apparatus of the present invention and rotated about its longitudinal axis so that it is driven into the ground for creating a relatively soil-free annulus between the casing means and the corresponding exterior surface of the pole. Suitable stabilizing filler material such as grout is then dispensed into a substantial portion of the annulus. The result is a repaired pole having a footing providing substantial strength which completely surrounds the deteriorated or damaged portion of the pole--accomplished without moving or cutting the pole.
Another object of the present invention is to provide an apparatus for cooperating with the casing means for installing same by driving it into the ground in an efficient manner, maintaining substantial concentricity between the longitudinal axes of the casing means and the elongate object or pole. Specifically, the apparatus of the present invention is directed to a driver means which is positionable about a circumferential portion of the casing means at the lower, above-ground region of the pole for engaging the casing means and rotating it about its longitudinal axis while simultaneously imparting a downwardly-directed force against the upper edge of the casing means thereby accomplishing the driving of the casing means into the ground to a predetermined depth.
Still another object of the present invention is to provide a driver means, as described above, with a special configuration which permits the driver means to be moved laterally toward the pole, thereby enabling the pole to be maintained as an integral unit with its attached lines. The novel configuration of the driver means is defined by a pair of jaw members which are pivotally interconnected adjacent one set of their ends and are openable for receiving the casing means therebetween and closable for surrounding the circumferential portion of the casing means to establish an operative drive mode for rotating the casing means and directing it ddownwardly into the ground.
A still further object of the present invention is to provide each of the above-described jaw members with a rotatable means operable for engaging the casing means and rotating it when the jaw members are disposed in the closed position, and power-driven means operatively coupled to the rotatable means for imparting rotation thereto. To accomplish this type of driver means construction, the rotatable means is defined by first and second half-cylinder shells, mounted respectively in the first and second jaw members. Each of the shells is oriented relative to one another to mate coaxially with the other, when the jaw members are disposed in the closed position, to define a rotatable cylinder dimensioned with a diameter greater than that of the casing means adapted for engaging the casing means and imparting rotation thereto.
Yet another object of the present invention is to provide transmission means operatively coupling the power-driven means to each half-cylinder shell for imparting rotation thereto when the jaw members are disposed in the closed position. The transmission means is defined by a pair of ring gear segments, one being slidably and rotatably mounted in each jaw member and secured to an associated half-cylinder shell. When the jaw members are disposed in the closed position, the ring gear segments become interconnected and complementary to form a continuous ring gear. Each of the half-cylinder shells is thereby rotated when the power-driven means is operated and includes a transfer means for engaging the casing means and imparting transferred rotation from the power-driven means to the casing means.
A still further object of the present invention is to provide a specific casing means configuration uniquely adapted for engagement with the transfer means mounted on the half-cylinder shells which have been described above. Specifically, the casing means is defined by a first cylindrical half-section conjoinable for assembly with a complementary cylindrical half-section so that an elongate longitudinal edge of each half-section overlaps a sidewall portion of the other half-section. The result is a pair of edges which may be engaged by the transfer means mounted on the half-cylinder shells so that rotation of the half-cylinder shells imparts rotation to the casing means.
A further object of the present invention is to provide an overall assembly for supporting the driver means and enabling selective positioning of the driver means. The assembly includes a boom assembly adapted to be mounted on a supporting structure, such as a vehicle, including an extendable-retractable boom arm adjustable for being selectively positioned so that the end of the boom arm, which supports the driver means, may be oriented at a preselected position relative to the ground. A mast assembly defining a mounting rack is supported on the end of the boom arm and holds the driver means, and a shifting means associated with the mast assembly is coupled to the driver means selectively operable for rectilinearly shifting the driver means therealong. The shifting of the driver means is necessary for imparting a downwardly-directed force to the casing means, when the jaw members are disposed in the closed position during rotation of the half-cylinder shells for driving the casing means into the ground.
A still further object of the present invention is to provide an assembly, as described above, which includes stabilizing means supported on the mast assembly disposed at an elevation above the driver means selectively operable for gripping and stabilizing the elongate object from substantial rotational movement during operation of the driver means in the drive mode .